On Sun, 2009-01-18 at 01:15 +0800, Alan Stern wrote: > On Sat, 17 Jan 2009, Zhao Yakui wrote: > > > The low-speed USB device is ignored by EHCI HCD, And when the uhci > > driver is loaded after EHCI driver, the low-speed USB device can be > > handler correctly. > > So we hope to resume EHCI before UHCI and see whether the exists the > > rediscovery and re-enumeration. > > Okay; go ahead. The order in which the drivers are loaded doesn't make > any difference. > > > In fact there exists quite a lot of delay in UHCI/EHCI driver. We want > > to use the parallel resume to reduce the resume time. > > Yes, that would be nice. > > > I also do another test, in which the EHCI hcd driver is resumed before > > UHCI. This is based on Intel ICH9 chipset. > > >1a.0/1a.1/1a.2 is UHCI > > >1a.7 is EHCI > > EHCI will be resumed before the corresponding UHCI. > > > > In my test there is no rediscovery and re-enumeration about > > low-speed USB device. And after it is resumed, the two low-speed device > > can still work well. > > First, are you testing suspend-to-ram or are you testing hibernation? > A good test would be hibernation and unplugging/replugging the mouse > while the system is asleep. An even better test would be > unplugging/replugging the computer's power cord while it is asleep. > > Second, can you provide the dmesg log showing what happens when you run > your test using a kernel with CONFIG_USB_DEBUG enabled? Thanks for the detailed explanation. I test it by using suspend to ram. In such case there is no rediscovery. Of course I will do the hibernation test and then send the detailed log to you. Thanks. > > > So my question is whether the EHCI can be resumed before UHCI. > > I'll have to see the detailed log of your test. I know that on my > ICH4 system, similar tests in the past have caused rediscovery. > > > If we > > can't, we want to do partial parallel. This means that the UHCI devices > > will be resumed parallelly . After the UHCI resume is finished, the ECHI > > will be resumed. But we don't know whether the resume order of root HUB > > should be considered. > > If we can, it will be very simple. > > That would be okay. If each UHCI and OHCI companion controller is > resumed before its partner EHCI controller, then the order of resuming > the root hubs doesn't matter. > > Alan Stern > -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
